Trailers in the trucking industry must be raised and lowered in order to mount or dismount a trailer from the cab. Trailers include a landing gear which acts to support the cab of the trailer when the trailer is not connected to a cab. Typically, an operator uses a crank handle connected to a shaft on the trailer landing gear to accomplish the raising or lowering of the trailer. While machine power may be utilized, the most cost effective method is to have the operator manually use the crank handle.
Necessarily, the movement of the crank handle will be against a force on the shaft. That is, to raise the trailer, the operator will push (or pull) on the crank handle to counteract the force of gravity pulling down on the trailer (i.e. the weight of the trailer). A number of devices may be used to give the operator a mechanical advantage in counteracting the weight of the trailer. In one system a ratchet on the crank handle is used, as seen in U.S. Pat. No. 7,021,659. However, none of these devices can eliminate the force needed to rotate the shaft. As the shaft is rotated, significant potential energy is stored in the trailer and trailer landing gear. If the crank shaft slips from the operator's grip, that potential energy will be released and cause the crank handle to spin about the shaft. This free wheeling counter rotation of the handle can be a significant danger to the operator with the potential to strike the operator, causing injury, loss of work, and increased operating costs for the trucking company. Because the mounting and dismounting of the trailer may need to be accomplished several times a day, any device that reduces the risk associated with this activity is potentially desirable.
The present invention overcomes one or more of these problems.